Pattern of P Availability in Different Soils as Assessed by Different Adsorption Equations

P adsorption data were fitted to Langmuir, Freundlich and Tempkin adsorption equations. Freundlich equation explained better the P adsorption behaviour than the Langmuir equation as evidenced by higher correlation coefficient values (ranged from 0.934 to 0.998). Adsorbed P increased with the increase in equilibrium P concentration. P desorption was far less compared to the P adsorption. The soils having higher clay content, CaCO₃ or extractable iron and aluminium exhibited high P adsorption but low P desorption indicating lower P concentration in soil solution for plant use at a point of time.